Field of the Invention
The present invention relates to an image forming apparatus in which a cartridge is configured to be attachable/detachable.
Description of the Related Art
A known image forming apparatus that forms an image on a recording material using an electrophotographic system employs a process cartridge system in which an electrophotographic photosensitive body (photosensitive drum) and a process unit acting on the electrophotographic photosensitive body are integrated into a process cartridge and the integrated process cartridge is configured to be attachable/detachable to/from an apparatus body. Since the process cartridge system allows a user to perform apparatus maintenance by himself/herself, it displays excellent usability and has been widely used in recent image forming apparatuses. Image forming apparatuses employing the process cartridge system may require a configuration in which a process cartridge attached to an apparatus body is positioned with respect to an apparatus body. For example, Japanese Patent Application Laid-open No. 2012-155166 discloses a configuration in which the position of an entire process cartridge in a drum axis direction is determined in the process of attaching the process cartridge to an apparatus body to determine the position of a photosensitive drum in the axis direction.
In the configuration of Japanese Patent Application Laid-open No. 2012-155166, however, a plurality of other components is interposed between a part positioned with respect to the apparatus body and the photosensitive drum in the process cartridge. Therefore, the dimensional accuracy, the assembling accuracy, or the like of the plurality of other components greatly influences the positioning accuracy of the photosensitive drum in a longitudinal direction.